diff --git a/projects/openttd_vs80.vcproj b/projects/openttd_vs80.vcproj
index 6dc649a8c8..cc986eb90e 100644
--- a/projects/openttd_vs80.vcproj
+++ b/projects/openttd_vs80.vcproj
@@ -53,6 +53,7 @@
 			/>
 			<Tool
 				Name="VCCLCompilerTool"
+				AdditionalOptions="/MP"
 				Optimization="3"
 				InlineFunctionExpansion="2"
 				EnableIntrinsicFunctions="true"
@@ -163,6 +164,7 @@
 			/>
 			<Tool
 				Name="VCCLCompilerTool"
+				AdditionalOptions="/MP"
 				Optimization="0"
 				AdditionalIncludeDirectories="..\objs\langs"
 				PreprocessorDefinitions="WIN32;_DEBUG;_CONSOLE;WIN32_ENABLE_DIRECTMUSIC_SUPPORT;WITH_ZLIB;WITH_PNG;WITH_FREETYPE;WITH_ICU;ENABLE_NETWORK;WITH_PERSONAL_DIR;PERSONAL_DIR=\&quot;OpenTTD\&quot;"
@@ -260,6 +262,7 @@
 			/>
 			<Tool
 				Name="VCCLCompilerTool"
+				AdditionalOptions="/MP"
 				Optimization="3"
 				InlineFunctionExpansion="2"
 				EnableIntrinsicFunctions="true"
@@ -371,6 +374,7 @@
 			/>
 			<Tool
 				Name="VCCLCompilerTool"
+				AdditionalOptions="/MP"
 				Optimization="0"
 				AdditionalIncludeDirectories="..\objs\langs"
 				PreprocessorDefinitions="WIN32;_DEBUG;_CONSOLE;WIN32_ENABLE_DIRECTMUSIC_SUPPORT;WITH_ZLIB;WITH_PNG;WITH_FREETYPE;WITH_ICU;ENABLE_NETWORK;WITH_PERSONAL_DIR;PERSONAL_DIR=\&quot;OpenTTD\&quot;"
diff --git a/projects/openttd_vs80.vcproj.in b/projects/openttd_vs80.vcproj.in
index f5d9f6d9d9..9fbcc4a138 100644
--- a/projects/openttd_vs80.vcproj.in
+++ b/projects/openttd_vs80.vcproj.in
@@ -53,6 +53,7 @@
 			/>
 			<Tool
 				Name="VCCLCompilerTool"
+				AdditionalOptions="/MP"
 				Optimization="3"
 				InlineFunctionExpansion="2"
 				EnableIntrinsicFunctions="true"
@@ -163,6 +164,7 @@
 			/>
 			<Tool
 				Name="VCCLCompilerTool"
+				AdditionalOptions="/MP"
 				Optimization="0"
 				AdditionalIncludeDirectories="..\objs\langs"
 				PreprocessorDefinitions="WIN32;_DEBUG;_CONSOLE;WIN32_ENABLE_DIRECTMUSIC_SUPPORT;WITH_ZLIB;WITH_PNG;WITH_FREETYPE;WITH_ICU;ENABLE_NETWORK;WITH_PERSONAL_DIR;PERSONAL_DIR=\&quot;OpenTTD\&quot;"
@@ -260,6 +262,7 @@
 			/>
 			<Tool
 				Name="VCCLCompilerTool"
+				AdditionalOptions="/MP"
 				Optimization="3"
 				InlineFunctionExpansion="2"
 				EnableIntrinsicFunctions="true"
@@ -371,6 +374,7 @@
 			/>
 			<Tool
 				Name="VCCLCompilerTool"
+				AdditionalOptions="/MP"
 				Optimization="0"
 				AdditionalIncludeDirectories="..\objs\langs"
 				PreprocessorDefinitions="WIN32;_DEBUG;_CONSOLE;WIN32_ENABLE_DIRECTMUSIC_SUPPORT;WITH_ZLIB;WITH_PNG;WITH_FREETYPE;WITH_ICU;ENABLE_NETWORK;WITH_PERSONAL_DIR;PERSONAL_DIR=\&quot;OpenTTD\&quot;"
diff --git a/projects/openttd_vs90.vcproj b/projects/openttd_vs90.vcproj
index 898410e4bb..a0dac02a85 100644
--- a/projects/openttd_vs90.vcproj
+++ b/projects/openttd_vs90.vcproj
@@ -54,6 +54,7 @@
 			/>
 			<Tool
 				Name="VCCLCompilerTool"
+				AdditionalOptions="/MP"
 				Optimization="3"
 				InlineFunctionExpansion="2"
 				EnableIntrinsicFunctions="true"
@@ -162,6 +163,7 @@
 			/>
 			<Tool
 				Name="VCCLCompilerTool"
+				AdditionalOptions="/MP"
 				Optimization="0"
 				AdditionalIncludeDirectories="..\objs\langs"
 				PreprocessorDefinitions="WIN32;_DEBUG;_CONSOLE;WIN32_ENABLE_DIRECTMUSIC_SUPPORT;WITH_ZLIB;WITH_PNG;WITH_FREETYPE;WITH_ICU;ENABLE_NETWORK;WITH_PERSONAL_DIR;PERSONAL_DIR=\&quot;OpenTTD\&quot;"
@@ -258,6 +260,7 @@
 			/>
 			<Tool
 				Name="VCCLCompilerTool"
+				AdditionalOptions="/MP"
 				Optimization="3"
 				InlineFunctionExpansion="2"
 				EnableIntrinsicFunctions="true"
@@ -368,6 +371,7 @@
 			/>
 			<Tool
 				Name="VCCLCompilerTool"
+				AdditionalOptions="/MP"
 				Optimization="0"
 				AdditionalIncludeDirectories="..\objs\langs"
 				PreprocessorDefinitions="WIN32;_DEBUG;_CONSOLE;WIN32_ENABLE_DIRECTMUSIC_SUPPORT;WITH_ZLIB;WITH_PNG;WITH_FREETYPE;WITH_ICU;ENABLE_NETWORK;WITH_PERSONAL_DIR;PERSONAL_DIR=\&quot;OpenTTD\&quot;"
diff --git a/projects/openttd_vs90.vcproj.in b/projects/openttd_vs90.vcproj.in
index 6ffe06eb96..2515946d83 100644
--- a/projects/openttd_vs90.vcproj.in
+++ b/projects/openttd_vs90.vcproj.in
@@ -54,6 +54,7 @@
 			/>
 			<Tool
 				Name="VCCLCompilerTool"
+				AdditionalOptions="/MP"
 				Optimization="3"
 				InlineFunctionExpansion="2"
 				EnableIntrinsicFunctions="true"
@@ -162,6 +163,7 @@
 			/>
 			<Tool
 				Name="VCCLCompilerTool"
+				AdditionalOptions="/MP"
 				Optimization="0"
 				AdditionalIncludeDirectories="..\objs\langs"
 				PreprocessorDefinitions="WIN32;_DEBUG;_CONSOLE;WIN32_ENABLE_DIRECTMUSIC_SUPPORT;WITH_ZLIB;WITH_PNG;WITH_FREETYPE;WITH_ICU;ENABLE_NETWORK;WITH_PERSONAL_DIR;PERSONAL_DIR=\&quot;OpenTTD\&quot;"
@@ -258,6 +260,7 @@
 			/>
 			<Tool
 				Name="VCCLCompilerTool"
+				AdditionalOptions="/MP"
 				Optimization="3"
 				InlineFunctionExpansion="2"
 				EnableIntrinsicFunctions="true"
@@ -368,6 +371,7 @@
 			/>
 			<Tool
 				Name="VCCLCompilerTool"
+				AdditionalOptions="/MP"
 				Optimization="0"
 				AdditionalIncludeDirectories="..\objs\langs"
 				PreprocessorDefinitions="WIN32;_DEBUG;_CONSOLE;WIN32_ENABLE_DIRECTMUSIC_SUPPORT;WITH_ZLIB;WITH_PNG;WITH_FREETYPE;WITH_ICU;ENABLE_NETWORK;WITH_PERSONAL_DIR;PERSONAL_DIR=\&quot;OpenTTD\&quot;"
diff --git a/projects/strgen_vs80.vcproj b/projects/strgen_vs80.vcproj
index 69304cb35f..014b4856b9 100644
--- a/projects/strgen_vs80.vcproj
+++ b/projects/strgen_vs80.vcproj
@@ -43,6 +43,7 @@
 			/>
 			<Tool
 				Name="VCCLCompilerTool"
+				AdditionalOptions="/MP"
 				Optimization="1"
 				FavorSizeOrSpeed="2"
 				PreprocessorDefinitions="STRGEN;WIN32;_DEBUG;_CONSOLE"
diff --git a/projects/strgen_vs90.vcproj b/projects/strgen_vs90.vcproj
index e28cd7d70f..9ea48ca28a 100644
--- a/projects/strgen_vs90.vcproj
+++ b/projects/strgen_vs90.vcproj
@@ -44,6 +44,7 @@
 			/>
 			<Tool
 				Name="VCCLCompilerTool"
+				AdditionalOptions="/MP"
 				Optimization="1"
 				FavorSizeOrSpeed="2"
 				PreprocessorDefinitions="STRGEN;WIN32;_DEBUG;_CONSOLE"